I saw no gorilla. I did see an individual, presumably human, sex indeterminate, dressed in a 'gorilla' suit, with improbably white lips.
I watched the video six times and counted 16 passes the first four, then 14, then 15, and watched it a few more times just to confirm 15. The pass from the taller guy, past the gorilla-suit, when the girl and the other guy reach for it could possibly have been a tip-off to him, which I originally counted as a pass. I did see the 'gorilla' the first time.
Interesting research and commentary. Good tip about the shoes.